Imaging and the detection and classification of objects is an important aspect of the operation of many systems, including satellite systems, marine vehicles, land based vehicles and aircraft. Imaging systems may be used to capture light within visual spectrum and reproduce in the visual spectrum a rendition of the image captured by one or more cameras. They may also be used to collect signals outside of the visual spectrum, which may be reproduced or conveyed as an image in the visual spectrum to provide information to people about a target, scene or environment. Imaging systems may also be used to perform detection or classification without necessarily having to reproduce an image.
Imaging systems generally include a camera that captures incoming light radiation and outputs signals or data in the form of an array of pixels. Each pixel in the array represents a portion of the image received by the camera and generally is defined by its pixel location, and color information, including the intensity of each color that comprises the pixel. In RGB imaging, the color information includes intensity data corresponding to the red, green and blue colors. The pixel data is stored and then may be used to reproduce a color image in the visual spectrum. Many consumer digital cameras and video cameras operate using the RGB pixel format.
A problem with all imaging systems is that scenes and targets of interest are frequently cluttered with glint, reflections or physical obstacles to a clear view. The imperfections in such scenes as perceived by the eye in the visual spectrum are reproduced in images rendered by RGB imaging systems. However, undesirable glint, reflections and in some cases physical objects may be filtered out of images captured by imaging systems using various well known techniques to process pixel data. Another technique to improve an image is to collect and process spectral information from more than three bands using more cameras. The additional spectral information associated with the additional bands beyond three bands is used to make a better, combined image, or to use the information from the additional bands to improve the ability to detect or classify objects captured by the imaging system.
Another problem of imaging systems is that while more cameras lead to more accuracy, they also lead to increase size and cost. For example, in multiple camera imaging systems, precise alignment and rigid mounting of the cameras is required to keep the cameras properly focused on the same field of view. The alignment and mounting is expensive and time consuming. The rigidity requirements also add size and weight that may be unacceptable for many applications. For vehicle applications of multiple camera imaging systems, the inevitable jarring and vibration may be detrimental to the camera alignment and the performance of the imaging system over time causing the need for periodic realignment and adjustment.
Accordingly, there remains a need for an imaging system that is capable of collecting more than three spectral bands with a minimum number of cameras. There is a further need for an imaging system that is capable of collecting more than three spectral bands that is compact, relatively inexpensive and that does not require elaborate alignment or include heavy mounting components.